Dry cell



May 16, 1939.

0. K. REINHARDT- DRY CELL Original Filed May 12,1952

INVENTOR OTTO If. fiE/NHARDT AITORNEYS m n M 3 3 R v 3 5 "A M v m i\m\ 1. w 2 6% F 1 W a C I Patented May 16, 1939 UNlTED STATES PATENTOFFICE DRY CELL Original application May 12, 1932, Serial No.

Divided and this application Decemher 23, 1936, Serial No. 117,281

3 Claims.

, connection with electric flashlights and hand lanterns, although notso limited.

ure for the upper end of the dry cell cup.

Another object of the invention is a closure which shall, when the cellsare superimposed one above the other in a flashlight, prevent theconductive bottom of the upper cell bridging the cen-' tral terminal ofthe lower cell and its cup to form a short circuit destructive of thecells. Accordingly, the closure is formed with a shoulder, or materialof the closure is otherwise 50 disposed that a straight line tangent tothe central terminal and the edge of the cup will pass through theclosure. More specifically, a straight line tangent to one terminal andthe closure will lie outside of the other terminal of the cell.

It isalso an object of the invention to provide an effective seal forthe flashlight cell. To this end, a closure portion snugly receives ametal cap for the end of the electrode.

A further object of the invention is to provide a closure for a dry cellwhichshall offer adequate or additional gas chamber space. Accordingly,the closure is ofinverted dish shape or convex and the space beneath theupwardly deflected portion is in communication with the space above thecartridge.

Still another object of the invention is to provide a metallic closurefor a dry cell which shall be insulated from the electrode. Aninsulating washer or bushing surrounds the electrode and supports themetallic closure and the exposed surface of the closure is coated orcovered with an insulating layer, such as enamel.

The invention also seeks a dry cell having effective means forpreventing either inward or outward displacement of the closure memberand at the same time preventing outward displacement of the electrode.To this end, the metallic cap for the electrode is preferably providedat its lower edge with a slight taper .or flare or the equivalent onwhich the closure or bushing rests or which engages the closure orbushing or which wedges tight into the closure-or bushing and theperiphery of the closure is secured to the edge of the cup as byclamping the same between a bead formed in the cup I and the inwardlydeflected edge.

Again, the invention has for its object a tight joint between a metallicclosure and the bushing, which insulates it from the central electrode.In accordance with this aspect of the invention, the

Theinvention has for one of its objects a 0105- hole in the bushing isslightly-smaller than the electrode so that, on assembly, the bushing iscaused to expand whereby the edge of the metal closure bites into or isembedded in the bushing. Yet another object of the invention is theprovision of a. closure or sealing means for a dry cell which ispractical from the standpoint of ease and cheapness of manufacture andconvenience, durability and reliability in use.

These and other objects of the invention and the means for theirattainment will be more apparent from the following detaileddescription, taken in connection with the accompanying drawingillustrating various embodiments by which the invention may be realized,and in which:

Figure 1 is a view showing the upper portion of a dry cell, parts beingbroken away to show details of this invention;

Figure 2 is a view, looking from above in Figure 1, parts being removedto show details;

Figure 3 is a fragmentary enlarged view of one aspect of the inventionshowing the joint between the bushing around the electrode and a metalclosure; and

Figure 4 is a fragmentary View showing the joint between a closureportion-and the contact cap according to another modification of theinvention.

This application is a division of Serial Number 610,791.

The invention is shown as applied to so-called 80 small dry cells ofthe'type commonly employed in connection with electric hand lamps andflashlights, but is applicable in whole or in its several aspects to anydry cell. A metallic cup l0, conveniently of zinc, such as shown inFigure 1, has a groove rolled in the wall to form an'inwardly directedhead or shoulder I2 proximate the rim or mouth of the cup ML. In all drycells, within such a cup, is usually disposed a cartridge formed of asuitable matrix composition conveniently molded about a carbon rodelectrode which projects upwardly, as at It.

After the cartridge has been inserted and, if desired, sealed in thecup, a closure member is applied thereto.

A metallic cap 22, say, of brass, is adapted to be disposed on the upperor protruding end of the carbon electrode, engaging it with a snug fit.Orr the bead may rest, if desired, a paper washer 0 Itis very desirablethat the joint between the closure, whether wholly of insulatingnon-metallic material as shown at 30 in Figure 4 or partly ofnon-metallic material and partly ofv metal as shown at 54, 55 in Figure1, be tight. To this end, the closure portion, either that portion ofthe non-metallic closure 30 surrounding the aperture or the bushing 55,is of insulating.

material and is formed with a central aperture less than the diameter ofthe metal cap, said material being inherently resilient so that whensaid closure portion and cap are forcibly assembled, the material willexpand into sealing contact with said cap. A portion of the closureengages the brass cap with a gas tight joint.

The insulating washer or bushing 55 is formed with a' flange 50 on whichrests the rim of the central aperture 52 of a convex closure 54 which,in this modification, is of metal. It will be observed that this mannerof assembling the closure portions 38 or 55 and cap 22 forms a gas tightseal. Were the closure in engagement with the relatively porous carbonelectrode, the escape of gases through the porous carbon around theclosure would be permitted, but since the cap is relatively not porous,gases cannot escape.

The closure 30 or 54 rests on the bead l2 or on the ilbrous washer 46thereon and the rim of the cup I is spun inwardly as a flange over theperiphery 34 of the closure 54 to clamp the same against the bead I2 oron thefibrous washer and hold it firmly in place with a gas tight joint.

The top may be enamelled'or otherwise coated with an insulatorymaterial, as at 58, so as to effectively insulate a superimposed cellfrom the metal of the closure and thus a superimposed cell contactingwith the metal central electrode 22 and withthe insulatory coating 58 onthe metal top is insulated and prevented from contacting with the edgel5 of the cup and becoming shortcircuited.

As shown, the closure 54 is convex or inverted dish shaped with itsperiphery or rim 34 offset from the main or convex portion 36 of theclosure in a plane therebeneath. The convex portion 36 may lie in asubstantially horizontal plane, as viewed in the drawing, or be somewhatdome shaped, and forming between the main portion 35 and the periphery34 a shoulder 38, the important feature being that material of theclosure is so disposed that a straight line tangent to the cap 22 andedge l5 passes through material 01' the top, or in other words, so thata straight line tangent to one terminal, say, the cap- 22 and theshoulder 38 will pass outside of the other electrode, say, the edge i5.Similarly, a line tangent twthe edge l5 and shoulder 38 will passoutside of the cap 22.

By so forming the-closure 54, several important advantages are attained.In the flrst place, by the upwardly ofiset or convex portion 36,additional space is provided therebeneath for gases generated in thecell in use and thus, if desired,

a shorter cell or longer cartridge may be used and yet adequate gasspace will be aiiorded. Also a closure,so shaped, may be availed of togive the cell more capacity, that is, space for active material.-Furthermore since the edge l5 of the cup is below the plane includingthe major portion of the closure, the cup may be of less height,

as shown in Figure 1. That is, because there is material displaced intothe bead, the height of the cup would have to be greater, were it notfor the downwardly deflected periphery of the closure, which permits ashorter cup to'be used, in fact, a cup'only as high as the usual cup fora dry cell in which no bead or inturned flange is found. As it is, thatamount of material is saved which, in quantity production, amounts to avery large saving. Furthermore, the convex or dish shaped top permitsthetop to encircle the brass cap while still permitting the rim of the cupto be disposed in accordance with standard practice some distancetherebelow. Another, and probably the most important advantage attainedby the convex top is that the convexity is preferably continued to apoint proximate the periphery and is at a point in a horizontal planeabove the horizontal plane including the inturned rim of the cup.- When,therefore, one cell is superimposed upon another in a flashlight (andthese cells generally loosely flt within the flashlight) should thesuperimposed cell be displaced slightly, that is, should its axis lie atan angle with respect to the axis of the cell upon which it rests, thebottom of the cell will contact with the central electrode and with thenon-conducting top but will not touch the rim of the cup to shortcircuit the cell. The bottom of the superimposed cell is indicated bythe broken line C in Figure 1. This is an important advantage becausedry cells in flashlights are frequently shortcircuited and destroyed andcaused to leak by reason of this bridging'oi the electrode and zinc cup.It will also be noted that should a cell touch the rim, it cannot at thesame time touch the central electrode, as shown by the broken line D inFigure 1.

The contact cap 22 of the Figure 1 disclosure may be modified as shownin Figures 3 and 4.

The metallic cap 22' or 42 for'the central carbon electrode i8 isconveniently formed with a flare or lip 44, which engages against theunderside of the closure 30 or the bushing 55. Such a flare or lip wouldprevent downward pressure of the edge as at 53 forcing the bushing 55downwardly into the cell. Also, when the closure is clamped in positionon the bead l2 by theinwardly spun edge I5 of the cup l0 any tendency ofthe electrode l8 toward axial movement or outward movement due tointernal causes within the cell plished by having the hole 52 in. themetal top slightly smaller in area than the cross-sectional areaof thebushing. Then, when the metal closure 54 is forcibly assembled with thebushing and the bushing then forced down over the brass cap, theconsequent deformation of the insulating material causes some materialto'be displaced over the edge of the metal, as shown at 60, in Figure 3,so that the metallic edge isembedded in the material. Thus a very tightjoint is obtained.

' b It will thus be seen that a dry cell has been the severalembodiments and in the selection and/or combination of diflerentcomponent elements in a dry cell, and no limitation is intended by thephraseclogy of the foregoing description or illustrations in theaccompanying drawing except as indicated in the'appended claims.

What is claimed is: v

1. In a dry 'cell, a metallic cup, a cartridge therein having anupwardly projecting substantially centrally disposed electrode, ametallic cap over the end of the electrode, a bushing oi insulatingmaterial formed with a central aperture receiving the metallic cap, saidbushing comprising a main portion and a peripheral flange extendingoutwardly from the lower portion-thereof, a metallic closure resting onthe flange of the bushing and having a central opening of a (11818- eterless than the initial diameter of the main portion of the bushing, saidinsulating material having inherent resiliency -sothat when said bushingis inserted in said closure aperture it is snugly received therein.

.end of the electrode, a bushing of insulating material formed with acentral aperture receiving the metallic cup, said bushing comprising amain portionv and a peripheral flange extending outwardly from the lowerportion thereof, a metallic closure secured to the upper edge of the cupand having a portion resting on the flange oi the bushing, said metallicclosure having a central opening or less diameter than the initialdiameter of the main portion of the bushing, the insulating ma- 7 auauu3 makeup the invention as a whole as well as in terial of said bushinghaving inherent resiliency so that when the bushing is inserted in theclosure aperture of the metallic closure it is snuglyreceived therein.

3. In a dry cell, a metallic cup, a cartridge therein having an upwardlyprojecting substantially centrally disposed electrode, a metallic cap onthe end of the electrode, a bushing of insulat- 'ing material formedwith a central aperture receiving the metallic cap, said bushing havingan'

